lib/tst_safe_file_at.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2021 SUSE LLC <rpalethorpe@suse.com>
 */

#define _GNU_SOURCE
#include <stdio.h>
#include "lapi/fcntl.h"
#include "tst_safe_file_at.h"

#define TST_NO_DEFAULT_MAIN
#include "tst_test.h"

static char fd_path[PATH_MAX];

const char *tst_decode_fd(const int fd)
{
	ssize_t ret;
	char proc_path[32];

	if (fd < 0)
		return "!";

	sprintf(proc_path, "/proc/self/fd/%d", fd);
	ret = readlink(proc_path, fd_path, sizeof(fd_path));

	if (ret < 0)
		return "?";

	fd_path[ret] = '\0';

	return fd_path;
}

int safe_openat(const char *const file, const int lineno,
		const int dirfd, const char *const path, const int oflags, ...)
{
	va_list ap;
	int fd;
	mode_t mode;

	va_start(ap, oflags);
	mode = va_arg(ap, int);
	va_end(ap);

	fd = openat(dirfd, path, oflags, mode);
	if (fd > -1)
		return fd;

	tst_brk_(file, lineno, TBROK | TERRNO,
		 "openat(%d<%s>, '%s', %o, %o)",
		 dirfd, tst_decode_fd(dirfd), path, oflags, mode);

	return fd;
}

ssize_t safe_file_readat(const char *const file, const int lineno,
			 const int dirfd, const char *const path,
			 char *const buf, const size_t nbyte)
{
	int fd = safe_openat(file, lineno, dirfd, path, O_RDONLY);
	ssize_t rval;

	if (fd < 0)
		return -1;

	rval = safe_read(file, lineno, NULL, 0, fd, buf, nbyte - 1);
	if (rval < 0)
		return -1;

	close(fd);
	buf[rval] = '\0';

	if (rval >= (ssize_t)nbyte - 1) {
		tst_brk_(file, lineno, TBROK,
			"Buffer length %zu too small to read %d<%s>/%s",
			nbyte, dirfd, tst_decode_fd(dirfd), path);
	}

	return rval;
}

int tst_file_vprintfat(const int dirfd, const char *const path,
		       const char *const fmt, va_list va)
{
	const int fd = openat(dirfd, path, O_WRONLY);
	int ret, errno_cpy;

	if (fd < 0)
		return -1;

	ret = vdprintf(fd, fmt, va);
	errno_cpy = errno;
	close(fd);

	if (ret < 0) {
		errno = errno_cpy;
		return -2;
	}

	return ret;
}

int tst_file_printfat(const int dirfd, const char *const path,
		      const char *const fmt, ...)
{
	va_list va;
	int rval;

	va_start(va, fmt);
	rval = tst_file_vprintfat(dirfd, path, fmt, va);
	va_end(va);

	return rval;
}

int safe_file_vprintfat(const char *const file, const int lineno,
			const int dirfd, const char *const path,
			const char *const fmt, va_list va)
{
	char buf[16];
	va_list vac;
	int rval, errno_cpy;

	va_copy(vac, va);

	rval = tst_file_vprintfat(dirfd, path, fmt, va);

	if (rval == -2) {
		errno_cpy = errno;
		rval = vsnprintf(buf, sizeof(buf), fmt, vac);
		va_end(vac);

		if (rval >= (ssize_t)sizeof(buf))
			strcpy(buf + sizeof(buf) - 5, "...");
		else if (rval < 0)
			buf[0] = '\0';

		errno = errno_cpy;
		tst_brk_(file, lineno, TBROK | TERRNO,
			 "vdprintf(%d<%s>, '%s', '%s'<%s>)",
			 dirfd, tst_decode_fd(dirfd), path, fmt, buf);
		return -1;
	}

	va_end(vac);

	if (rval == -1) {
		tst_brk_(file, lineno, TBROK | TERRNO,
			"openat(%d<%s>, '%s', O_WRONLY)",
			dirfd, tst_decode_fd(dirfd), path);
	}

	return rval;
}

int safe_file_printfat(const char *const file, const int lineno,
		       const int dirfd, const char *const path,
		       const char *const fmt, ...)
{
	va_list va;
	int rval;

	va_start(va, fmt);
	rval = safe_file_vprintfat(file, lineno, dirfd, path, fmt, va);
	va_end(va);

	return rval;
}

int safe_unlinkat(const char *const file, const int lineno,
		  const int dirfd, const char *const path, const int flags)
{
	const int rval = unlinkat(dirfd, path, flags);
	const char *flags_sym;

	if (!rval)
		return rval;

	switch(flags) {
	case AT_REMOVEDIR:
		flags_sym = "AT_REMOVEDIR";
		break;
	case 0:
		flags_sym = "0";
		break;
	default:
		flags_sym = "?";
		break;
	}

	tst_brk_(file, lineno, TBROK | TERRNO,
		 "unlinkat(%d<%s>, '%s', %s)",
		 dirfd, tst_decode_fd(dirfd), path, flags_sym);

	return rval;
}